If a speaker at one of his seminars began to explain how he had come by his ideas, the great Russian theoretical physicist L.D. Landau would stop him with disdain: ‘That is only an item for your autobiography.’ Landau died before reaching the age of reminiscence, but Rudolph Peierls was his friend and Nevill Mott was another near-contemporary. Now that they are both about eighty, they may feel able to risk his posthumous scorn. Mott is a sort of father-in-science to me, and Peierls an uncle. Yet it never occurred to me, until I read these memoirs, how very alike their careers have been. They both grew up into theoretical physics just after the quantum breakthrough of 1925, and quickly made their names in exploiting this new instrument of thought to solve a whole range of old problems. They both made outstanding contributions to the theory of metals and other solids. Both of them were professors at Redbrick universities before they were thirty – Mott at Bristol and Peierls at Birmingham. When they came back from wartime research in 1945, each was offered – in due order of age, I suppose – the Chair of Theoretical Physics at Cambridge, and each duly turned it down. Eventually, Oxbridge got them both – Mott as Cavendish Professor at Cambridge and Peierls as head of the school of theoretical physics at Oxford. They were both knighted. They both have strings of honorary degrees. Mott got a Nobel Prize in 1977. They say that Peierls would have got one too, if only his contributions to physics had been concentrated in a narrower field. Neither of them has clambered high up the pyramid of state power, but they have both been active in academic and scientific affairs. They also have one other feature in common: they both gave scientific employment to Klaus Fuchs and worked closely with him for a number of years without the least suspicion that he was not as he seemed.